Welding copper and the like



March 18, 1930. T. E. MURRAY, JR.) Er Al.

WELDING COPPER AND THE LIKE File'd July 5, 192'7 2 Sheets-SheetINI/ENTOR f/vA/Err uut/,f1 TTORNEY I/ n \\\|1/ &T)\\ 1S XU 7/ `r. D L 115 l ,U L l/ 4/ H n. E L

March 18, 1930. T. E. MURRAY, JR., 5r AL 1,750,643

WELDING COPPER AND THE LIKE Filed July 5. 1927 a sheets-sheet 2 v 1NVENTUR OMAJ.' MHRA y :ff-ra Patented Mar. 18, i930 'TfUNl'rED ys'luxrlasPATENT ol-I-lclaz THOMAS E. MURRAY, JR., AND IRVING T. BENNETT, FBROOKLYN, YORK;

SAID BENNETT ASSIGNOR TO ".'LIEIOMAS E. MURRAY, 0F BROOKLYN, NEW 'YORKWELDING COPPER AND TEE LIKE Application led July 5, 1927'. Serial No.203,438.'

The invention aims to provide certain improvements in the uniting ofcertain metals by which a better and more durable union can be obtainedthan by previous methods. There .are diiiiculties in the ordinarymethods of butt, spot, projection or similar welding when appliedto-metals whose electrical and thermal conductivity is high. Such forexample are copper, aluminum and brass,-particu larly the irst. rlhevpresent invention provides a method having advantages referred tohereinafter in" the making of all welded joints and particularly in thewelding operations and methods above named.

rlhe accompanying drawings illustrate applications of the invention.

Figs. l and 2 illustrate in successive stages the uniting of aradiatingl structure to a steam pipe in the making of radiators;

Fig. 3 is a side elevation of part of such a radiator; j

Fig. i is a view similar to Fig. 2 ci a modified structure;

Fig. 5 is an enlarged diagram illustrating f the structure vof the weld;A

Figs. 6, 7 and 8 are sectional views before A welding illustratingmethods di'ering in detail; and A Figs. 9 and 10 are sectional views ofother applications of the invention.

Figs. l to 8 illustrate the application to a steam pipe 1 of a radiatingstructure comprising metal sheets corrugated in horizontal section toform laterally extending tins 2 and j longitudinally extending portions3 which are bent outwardly at intervals to formrecesses 4 embracing thepipe l between them. The corrugated plates are preferably of copper orcopper alloy, though other metals may e used. lt is important in unitingthe parts ot such a radiator to make a joint which is not liable toloosen under the expansion andcontraction of Ithe parts. The snotweldingv of'copper is almost or quite impracticable because of the rapidconduction oil-the current and the heat from the points to be joined aswell as the high electrical conductivity ci' the metal itself.

rlhis difiiculty'is avoided by the present invent-ion however. Weldingstraps 5 ot iron or steel are provided with recesses 6 so that theyembrace the copper sheet varound and at points beyond the pipe. Theopposite straps 5 are then welded to each other to form joints extendingbetween the opposite steel or iron straps 5 and through the copperplates 3.

Fig. 4 shows a similar met iod of attaching a single copper plate 3 tothe pipe l. A copper plate is recessed at 4 to extend partly around thepipe. Steel straps 5 similarl to those ot' Fig. l are placed in positionand welded to each other as at 8 through the single copper sheet 3 so asto unite the pipe to the sheet.

The method is particularly useful in uniting sheets of copper to oneanother or in uniting a sheet of copper to some other part such as thesteam pipe illustrated by Fig. li. nd for making a joint with copper,the straps are preferably oi steel. But the invention may be applied tomaking oints with various other metals instead of copper, and usingstraps or similar pieces of metal having a lower conductivity than thatthrough which the weld extends. i

Fig. 5 illustrates the structure ci the resulting weld. IThe metal ofthe straps 5 is pressed in slightly at the joint. rlhe heat and pressurecause the interposed sheets 3 at this point to alloy with or dissolveinto the steel so that'the central portion of the joint 7 is of a copperiron alloy. At the same time some of the copper from the sheets 3 issoftened and forced down in the form of a llet 9 against the pipe l.IThis illet and the recessed portions i are pressed so closely againstthe pipe as in their heated condition to make a very intimate union withthe latter.

rlhe invention may be appliedto various kinds of electric welding. Figs.6, 7 and 8 illustrate the use of the projection method in which, inorder to localize the heat, a. projection is formed between the parts tobe welded. ln Fig. 6, one of the straps 3 is provided before weldingwith a pressed out portion 10. Or there may be provided, as in Fig. 7, atubular projection 1l punched out from the strap. Or as in Fig. 8, aprojection l2 may be provided bysplitting the strap and bending it outin the form of a tongue. Various liti@ other methods areknown of formingsuch projections. lt is preferable to provide projections on only one ofthe two co-operating straps. 'This is sucient to secure a good weld andavoids the necessity of bringingI projections from two opposite strapsinto aclcurate registration with each other.

Where an additional part is to be assembled with the copper sheet orsheets, such as the pipe 1, the outside welding piece is preferably inthe form of a strap passing around the additional part. Fig. aillustrates a single strap for a single tube 1. Fig. 3 illustrates theapplication of the radiating structure to a pipe arranged in threesuccessive lengths, with a single strap'extending over all the joints ina vertical line. ln assembling other structures by this method, piecesof steel or the like of various othershapes may be used instead ofstraps.V

j The improved/welds provide a strong and durable connection and-arewell adapted to economical production. Each weld requires acomparatively small quantity of electrical current so that a largenumber of such welds may be made at one operation by an apparatus havingelectrodes at the desired locations. For example, the six joints shownin Fig. 3 maybe made ati one operation. Or several such groups of sixjoints each maybe made to unite the whole or any part of the assembledstructure at one operation. A suitable apparatus forthis purpose isillustrated in pending application, Serial No. 91,023 filed February 27,1926. The radiatorand welded structures disclosed herein are claimed ina sepaate application No.l 203,437, led July 5, 192 Y The previouslydescribed figures illustrate the application of the invention to eitherone or two copper sheets to be joined. rlhe number may be increased.Fig. 9 shows the invention applied to the uniting of six sheets 13 ofcopper by means of steel strips 14 with spot welds 15 at intervalsbetween the opposed seel strips extending through the copper s eets.

Fig. 10 illustrates the invention applied to Vsheets through which theweld -is passed are of dilerent metals; as for example, one of copperand one of aluminum. In certain cases also it will be advantageous toutilize the invention by welding two outer pieces made/as through anintermediate piece or pieces of metal the same as or similar inconductivity to the outer pieces.

The use of steel (in which term l include Aferrous metals generally) forstraps in aradiator having the heating element -or the radiatingstructure or both of copper (in which 'term l include cuprous metalsgenerally) has tween the heating element and the radiatingv structure isincreased.

lt is of prime importance that the radiating structure shall make asintimate contact as possible with the heating element so as to conductthe heat from the latter as rapidly as possible and this purpose isgreatly aided by the comparative expansion of' the copper l parts andthe steel straps when the radiator` is heated. There will be someexpansion of the steel straps; but this will be within the elastic limitso. that when the radiator is cooled the straps will be restored totheir original dimensions and will hold the parts of the radiatortogether with substantially their original efliciency.

Various other modilications may be made by those skilled in the artwithout departing from the invention as dened in the following claims.

What We claim is 1. The method of making a lap joint be tween two piecesof metal of comparatively high conductivity which consists in applyingat opposite sides thereof pieces of metal of comparatively lowconductivity and electrically welding the latter together through themetal of the pieces of higher conductivity.

2. The method of making a lap joint between two pieces of copper or thelike which consists in applying at opposite sides thereof pieces ofsteel and electrically Welding the latter through the pieces of copper.r

3. The method of uniting two sheets ot copper With a third elementembraced between them which consists in applying at opposite sides ofthe copper at points adjacent to the third element, pieces of steel andelectrically welding thel latter to each other through the copper.

4:. The method of uniting a plurality of sheets of metal ofcomparatively high conductivi which consists in applying at oppositesides thereof pieces of metal of comparatively low conductivity andelectrically welding the latter to each other through the sheets ofhigher conductivity.

5. The method of applying a radiating structure to the heating elementof a radiator which consists in assembling said radiating structure andheating element between pieces of metal having a lower coefficient ofthermal expansion than said heating element and welding such parts to'each other through the radiating structure at points adjacent to theheating element so that when the radiator is heated the degree ofcontact between the rediating structure will be-increased.

6.. The method of applying a radiating structure to a copperheatingelement ofv a -radiator which consists in assembling said ingstructure embracing the tube, applying steel straps tting the outer faceof the portions of the radlating structure Which embrace the tube andwelding said straps'to each other through the radiating structure atpoints adjacent to the tube so that when a heating medium is passedthrough the tube the latter will expand to a greater extent than thestra s and will increase the de ree of contact etween the tube and thera iating structure.

In witness whereof, We have hereunto.

names. THOMAS E. MURRAY,A JR. IRVING T. BENNETT.

signed our

